GEOLOGY AND TOPOGRAPHYf 



OF 



THE LEAD KEGION. 



OHAPTEE I. 



II^TEODUCTOET AlilT) HISTOEICAL. ' 



Survey of 1873. In accordance with my instructions received 

 from the late Dr. I. A. Lapham, in May, 1873, to make a survey of 

 two lines, with sections of the strata; one north and south, and the 

 other east and west, crossing at or near Mineral Point, work was com- 

 menced on the 5th of June, 1873, at Scales Mound, 111., as being 

 near the southern boundary of the Lead region. 



The territory examined during the year 1873 is as follows: Town 

 29 N., ranges 2 and 3 E., in the state of Illinois ; towns 1 to 13 inclusive, 

 in ranges 2 and 3 E., in the state of Wisconsin ; towns 4 and 5, on 

 ranges 1 to 6 W., to the Mississippi river; towns 4 and 5, on ranges 

 1, 2, 3, 4 and 5 E.; towns 6, 7, 8 and 9, on ranges 5 and 6 E., to the 

 Wisconsin river, being in all an area of about 50 townships. 



Explorations were chiefly confined to the territory already men- 

 tioned; departures were, however, occasionally made for the purpose 

 of visiting localities of geological interest or mineralogical import- 

 ance. In order to complete the survey of so large a tract of country, 

 it was necessary to traverse an average area of twelve square miles 

 per day. Such an amount precluded anything more than a careful 

 examination of the more important localities, and a general inspection 

 of the rest. 



The advantages of this plan of operations were numerous, but 

 chiefly these: that by the examination of a tract of country twelve 

 miles in width, passing through the center of Grant, Iowa and La 

 Fayette counties, a large and comprehensive view of the entire Lead 

 region was secured, so far as its general features were concerned; the 



